Liquid metal heat exchanger

ABSTRACT

A liquid metal heat exchanger providing for a single pass of primary liquid metal and two passes of secondary liquid metal consisting of a removable core suspended at the top by an annular tube sheet clamped by a bolted ring for convenient removal. A funnel leading into a central downcomer separates cold incoming secondary liquid metal from the relatively hot outgoing secondary liquid metal.

0 United States Patent [151 3,656,543 Wolowodiuh et a1. [45] Apr. 18,1972 [54] LIQUID METAL HEAT EXCHANGER 1,990,251 2/1935 Potter ..l65/75 x3 059 908 10/1962 Fox et al.... ..165/74 [72] Inventors: WalterWolowodruk New Provldence;

Tobias stem, Rockaway, both of Ni 3,325,374 6/1967 Margen ..l22/32 X[73] Assignee: Foster Wheeler Corporation, Livingston, FOREIGN PATENTSOR APPLICATIONS 835,266 5/1960 Great Britain ..l76/65 [22] Filed: May25, 1970 P I E Ch 1 S k l rzmary xammerares u a0 [21] Appl' 40,036Attorney-Roland A. Anderson 52 use: ..165/74,165/l58, 176/65, 7] TR 51 ICl A liquid metal heat exchanger providing for a single pass of 58 F ldlllll IIIIIIIIIIIIIIIIIIIIIIIIII 15g 161 P mary liquid metal and twopasses of secondary liquid metal 1 1e 0 /32 i consisting of a removablecore suspended at the top by an annular tube sheet clamped by a boltedring for convenient removal. A funnel leading into a central downcomerseparates [56] References cued cold incoming secondary liquid metal fromthe relatively hot UNITED STATES PATENTS Outgomg Secondary q metal-3,490,521 1/1970 Byerley ..l65/161 9Claims,4Drawing Figures PATENTEDAER18 1912 INVENTORS WALTER WOLOWOD/UK TOBIAS STERN BY ATTORNEY LIQIJWMETAL HEAT EXCHANGER BACKGROUND OF THE NVEN'lION The invention describedherein was made in the course of, or under, a contract with the UnitedStates Atomic Energy Commission.

In the development of liquid metal fast breeder reactors, it isnecessary to produce effective and reliable heat exchange apparatus forthe transfer of heat from the primary liquid metal reactor coolant tosuitable secondary liquid metal. A typical liquid metal suitable forthis application is molten sodium.

Among the difficulties involved in the design and development ofsuitable heat exchange apparatus are those having to do with conductingmaintenance operations in a liquid sodium environment, absorbingstresses induced by thermal gradients, and others which will becomeapparent from the description of this invention.

SUMMARY OF THE INVENTION The present invention overcomes drawbacks inthe prior art, such as the difficulties mentioned above by providingheat exchange apparatus in which the tubes are readily accessible formaintenance and repair, and incorporating a thermal barrier to reducethermal stresses as a result of temperature differences between the coldincoming secondary liquid metal and the remaining sodium in theapparatus.

It is thus one of the objects of this invention to provide an improvedheat exchanger with improved maintenance and repair features and reducedthermal stresses.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevation view in sectionof a heat exchanger made in accordance with this invention;

FIG. 2 is a view along 22 ofFIG. 1;

FIG. 3 is a sectional view showing in detail a portion of the heatexchanger of FIG. I; and

FIG. 4 is a sectional view showing in detail another portion ofthe heatexchanger of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the figures, heatexchanger consists of an outer cylindrical shell 12 forming a lowersection of the heat exchanger 10 and having a curved bottom 14 having aprimary outlet 16. Adjacent to the upper end of the shell 12 is aprimary inlet 18 above which is a cylindrical upper section 22 which isprovided on one side with a secondary outlet 24 in the lower portionthereof. The upper section 22 is of larger diameter than the shell 12. Asecondary inlet 26 is located in section 22 at a location above that ofsecondary outlet 24. The top of upper section 22 is closed off with aninverted hemispherical head 28 having a flange 32 which is bolted to aflange 34 of upper section 22. Inverted head 28 reduces the liquid metalcontent on the secondary side.

It will be seen that at the top of the lower section 12 is a flange 34which forms the lower end of the upper section 22. The flange 34 formsthe support for a removable core 35 which is positioned within thesection 22. Clamping ring 36 holds in place an annular tube sheet 38while bolts 42 spaced along ring 36 threaded into flange 34- hold theformer in place.

Extending down into lower section 12 is a downcomer tube 44 which at thelower end thereof supports a lower annular tube sheet 46 from whichextends an elliptical head 48 forming a collection compartment 52.Spacer brackets 54 are provided for centering purposes.

The upper end 55 of downcomer tube 44- attaches to the lower face of theupper tube sheet 38 which in turn rests on flange 34. A welded omegaseal 56 is provided between the upper tube sheet 38 and the flange 36.

A funnel-like member 53 having a lower cylindrical portion which extendsdown into downcomer tube 44 and an upper portion which flares upwardlyand outwardly is bolted at its peripheral marginal portion to a supportring 59 which is mounted on the inside wall of the upper section 22. Thelower portion of the funnel-like member 53 extends down into downcomertube 44 to serve as a thermal barrier to reduce the thermai stresses intube sheet 33 and also to reduce leakage of incoming cold secondarysodium into outgoing hot secondary sodium chambers. A thin sleeve 69(FIG. 3) made of stainless steel in its upper portion and of a materialhaving a lower coefficient of expansion than stainless steel in itslower portion is posit oned snugly between the upper tube sheet 38 andthe lower portion of member 58 to reduce further the leakage ofsecondary sodium.

A second flared member 61 located below the funnel member 58 isconnected with that section through a cylindrical member 62 whichextends from the outer edge of the section 6?. upwardly to the funnelmember 58 as shown best perhaps in MG.

The upper funnel member 58 is thick enough to withstand the pressure ofthe secondary fluid and the lower flared member 61 is made thin enoughto serve as a thermal barrier for the upper funnel 58. Metallic thermalinsulation 63 reduces the thermal gradient in the portion of the uppersection 22 located between the secondary fluid outlet nozzle 24 and thesupport ring 59.

Connecting upper and lower tube sheets 38 and 46, respectively, is anannular assembly of tubes referred to as tube bundle 66, welded at bothends to their respective tube sheets. Flow battles 63 also serve a tubesupports. The baffle arrangement is not a part of this invention, beingpart of an invention covered by U.S. application Ser. No. 8501, entitledLiquid Metal i-ieat Exchanger, filed Feb. 4, 1970 in the name of WalterWolowodiuk, one of the inventors herein. A plurality of inner and outerspaced tie rods 72 and 74 respectively, having sleeves interconnect theflow baffles by welding and bolting as shown in FIG. 2 to obtain a morerigid structure.

in the operation of heat exchanger 16, hot primary sodium enters throughinlet 18, circulates around the tubes in bundle 66, filling the annularspace around downcomer 44 and leaves through outlet 16 at the bottom ofshell 12. Single marked arrows show primary flow while double headedarrows show secondary flow. Relatively cold secondary sodium entersthrough upper nozzle 26, flows downward through funnel-like member 58,downcomer tube 44, and into lower compartment 52. The sodium then passesup through tube sheet 46 into the tubes of bundle 66, through tube sheet38 and out through nozzle 24.

In the arrangement described, the construction permits tube pluggingwithout removing the tube bundle 66. This is accomplished by removinginverted hemispherical head 28 and the upper funnel-like member 58 withits associated lower member 64 which exposes upper tube sheet 38 formaintenance work. For the removal of bundle 66, ring 36 is unbolted andlifted out, omega seal 56 is cut and bundle 66 is lifted out of shell12.

What is claimed is:

l. A liquid metal heat exchanger comprising:

a cylindrical shell having an upper section and a lower section;

a funnel-shaped member in said upper section, said member beingremovably attached at the periphery thereof to said upper section;

an axially disposed removable core means extending down into the lowersection of said shell; said core means comprising a cylindrical tubeextending down into said lower section and positioned so that the narrowpart of said funnel communicates with said tube; a lower annular tubesheet mounted on the bottom of and surrounding said tube; a closureenclosing the bottom of said tube and lower tube sheet forming a lowercompartment; an upper annular tube sheet encircling said tube andremovably attached at its periphery to said shell; and a bundle of tubesextending between said upper and lower tube sheets to complete a flowpath of secondary coolant flowing down through said funnel-shapedmember, tube, lower compartment, and up through said bundle of tubes;

means in said upper section f! suspending and clamping the top of saidremovable core means at the periphery of said upper tube sheet;

a secondary sodium inlet and a secondary sodium outlet in said uppersection, said inlet and outlet both being in the side wall of said uppersection of said shell at a location laterally beyond the peripheries ofsaid upper and lower annular tube sheets, said inlet being laterallybeyond the periphery of said funnel-shaped member, said inlet directingfluid over said funnel-shaped member to flow downward through said tube,said outlet being disposed below said funnel-shaped member but abovesaid upper tube sheet to direct secondary fluid coming out of said tubebundle out of said exchanger; and

a primary sodium inlet in the upper portion of said lower section saidprimary sodium inlet being laterally beyond said bundle of tubes andsaid lower tube sheet, and a primary sodium outlet below said lowerchamber.

2. The liquid metal heat exchanger defined in claim 1 wherein said meansfor suspending and clamping the top of said removable core meanscomprises an annular flange, said upper tube sheet being removablyconnected with said flange.

3. The liquid metal heat exchanger defined in claim 2 wherein said meansfor suspending and securing the top of said removable core means furthercomprises a clamping ring bolted to said flange, said clamping ringclamping said upper tube sheet between said ring and said flange.

4. The liquid metal heat exchanger defined in claim 3 wherein said uppertube sheet is supported upon the top of said cylindrical tube.

5. The liquid metal heat exchanger defined in claim 4 further comprisinga head, said head closing the top of said upper section and being boltedabout its periphery to the top of said upper section.

6. A heat exchanger for placing two fluids in indirect heat exchangecomprising: a shell; an intake in the side wall of said shell for afirst of said fluids; an exhaust for said fluid positioned below saidintake; a tube; a first annular tube sheet and a second annular tubesheet, said tube sheets encircling and being axially positioned withrespect to said tube, said first tube sheet being closer to said intakethan said second tube sheet; a tube bundle extending between said tubesheets; a chamber contiguous to said second tube sheet whereby saidfirst fluid comes in through said intake, flows over said tube bundleoutside of said chamber and exits at said exhaust, an inlet for a secondof said fluids, said inlet being positioned laterally of said tubesheets, a funnel-like member for directing said second fluid from saidinlet to said tube; an outlet for the second of said fluids, said outletbeing between said first tube sheet and said funnel-like member, wherebysaid second fluid comes in through said inlet, passes through saidfunnel and said tube to said chamber, then passes through said tubebundle and out said outlet, said funnel-like member and said first tubesheet being removably secured at their peripheries to said shell topermit access to said tube bundle by moving said funnel and then saidfirst tube sheet and attached tube bundle axially out of said shell.

7. The heat exchanger defined in claim 6 further comprising a supportring, the peripheral marginal portion of said funnellike member beingbolted to said ring.

8. The heat exchanger defined in claim 6 further comprising a clampingring, said clamping ring being positioned over the outer peripheralmarginal portion of said first tube sheet and bolted to said heatexchanger.

9. The heat exchanger defined in claim 8 wherein said tube and said tubebundle are substantially vertically disposed with said first tube sheetat a higher elevation than said second tube sheet, said funnel-shapedmember having a lower cylindrical portion extending down into said tube,said first tube sheet having an inner marginal portion resting on thetop of said tube.

1. A liquid metal heat exchanger comprising: a cylindrical shell havingan upper section and a lower section; a funnel-shaped member in saidupper section, said member being removably attached at tHe peripherythereof to said upper section; an axially disposed removable core meansextending down into the lower section of said shell; said core meanscomprising a cylindrical tube extending down into said lower section andpositioned so that the narrow part of said funnel communicates with saidtube; a lower annular tube sheet mounted on the bottom of andsurrounding said tube; a closure enclosing the bottom of said tube andlower tube sheet forming a lower compartment; an upper annular tubesheet encircling said tube and removably attached at its periphery tosaid shell; and a bundle of tubes extending between said upper and lowertube sheets to complete a flow path of secondary coolant flowing downthrough said funnel-shaped member, tube, lower compartment, and upthrough said bundle of tubes; means in said upper section for suspendingand clamping the top of said removable core means at the periphery ofsaid upper tube sheet; a secondary sodium inlet and a secondary sodiumoutlet in said upper section, said inlet and outlet both being in theside wall of said upper section of said shell at a location laterallybeyond the peripheries of said upper and lower annular tube sheets, saidinlet being laterally beyond the periphery of said funnel-shaped member,said inlet directing fluid over said funnel-shaped member to flowdownward through said tube, said outlet being disposed below saidfunnel-shaped member but above said upper tube sheet to direct secondaryfluid coming out of said tube bundle out of said exchanger; and aprimary sodium inlet in the upper portion of said lower section saidprimary sodium inlet being laterally beyond said bundle of tubes andsaid lower tube sheet, and a primary sodium outlet below said lowerchamber.
 2. The liquid metal heat exchanger defined in claim 1 whereinsaid means for suspending and clamping the top of said removable coremeans comprises an annular flange, said upper tube sheet being removablyconnected with said flange.
 3. The liquid metal heat exchanger definedin claim 2 wherein said means for suspending and securing the top ofsaid removable core means further comprises a clamping ring bolted tosaid flange, said clamping ring clamping said upper tube sheet betweensaid ring and said flange.
 4. The liquid metal heat exchanger defined inclaim 3 wherein said upper tube sheet is supported upon the top of saidcylindrical tube.
 5. The liquid metal heat exchanger defined in claim 4further comprising a head, said head closing the top of said uppersection and being bolted about its periphery to the top of said uppersection.
 6. A heat exchanger for placing two fluids in indirect heatexchange comprising: a shell; an intake in the side wall of said shellfor a first of said fluids; an exhaust for said fluid positioned belowsaid intake; a tube; a first annular tube sheet and a second annulartube sheet, said tube sheets encircling and being axially positionedwith respect to said tube, said first tube sheet being closer to saidintake than said second tube sheet; a tube bundle extending between saidtube sheets; a chamber contiguous to said second tube sheet whereby saidfirst fluid comes in through said intake, flows over said tube bundleoutside of said chamber and exits at said exhaust, an inlet for a secondof said fluids, said inlet being positioned laterally of said tubesheets, a funnel-like member for directing said second fluid from saidinlet to said tube; an outlet for the second of said fluids, said outletbeing between said first tube sheet and said funnel-like member, wherebysaid second fluid comes in through said inlet, passes through saidfunnel and said tube to said chamber, then passes through said tubebundle and out said outlet, said funnel-like member and said first tubesheet being removably secured at their peripheries to said shell topermit access to said tube bundle by moving said funnel and then saidfirst tube sheet and attached tube bundle axially out of said shelL. 7.The heat exchanger defined in claim 6 further comprising a support ring,the peripheral marginal portion of said funnel-like member being boltedto said ring.
 8. The heat exchanger defined in claim 6 furthercomprising a clamping ring, said clamping ring being positioned over theouter peripheral marginal portion of said first tube sheet and bolted tosaid heat exchanger.
 9. The heat exchanger defined in claim 8 whereinsaid tube and said tube bundle are substantially vertically disposedwith said first tube sheet at a higher elevation than said second tubesheet, said funnel-shaped member having a lower cylindrical portionextending down into said tube, said first tube sheet having an innermarginal portion resting on the top of said tube.